I have one regular stud for mounting a bipod at the forearm and then two pairs of what I think you're calling flush cups on the bottom and off side of the rifle. All I want to know is what I need to buy to attach a sling to this stock--Mcm A-3.
Thanks, Drew

Try this Midway link and see if it helps. I'm not sure if they sell the swivel separately and not with the base, but I've bought several of this combo from them. I've had flush cups that McMillan installed and the swivels from this combo fit the cups that McMillan had installed.